On 14.08.2014 03:22, ok@cs.otago.ac.nz wrote:
Let's say the user entered:
No, Name, Qty, Price -------------------------------------------- 1. [ ] [99] [10] 2. [Water ] [ ] [10] 3. [Juice ] [ 1] [ ]
The GUI should display total of 990, Why? Let's be clear about this: given that information, the total is unknown and unknowable, and even if lines 1 and 2 were intended to be the same line, the existence of line 3 means that 990 is almost surely LESS than the correct total, whatever that might be.
Because this is what you would get in the most familiar software for accountants, and the most widespread functional language in the world: a spreadsheet. Or simply because this has been specified this way and the developer is supposed to implement it.
Supermarkets here don't let you create invoice lines by reference (giving a possibly garbled name) but only by ostension ("I want to buy THIS"). This is why all those bar codes and thingies exist. Libraries here do something similar with books: you show the machine "I want to borrow THIS book" and a guaranteed valid line is created.
Imagine you are a freelance programmer and you are in the process of invoicing your customer.
A possible data point: students here are very much used to the instant feedback provided by syntax colouring editors, and few of them would willingly program without such tools. (I'm annoyed by and slowed by this nonsense, but tastes vary.) Heh, I also like syntax colouring editors, vim specifically. Recently I saw SublimeText, and I also liked it very much, I almost switched from vim. I keep promising to myself that I would learn Emacs. I don't like Eclipse, because it is too slow.
This is evidence that at least some people strongly prefer instant feedback; by the time they get to the end of a form they know that each and every field is at least plausible taken by itself.
So in the end you admit that my "design" (scratch, rather) might be what young people might like? -- Kind regards, Wojtek Narczynski